Shares of Straight Path Communications (NYSEMKT: STRP) were up 12.8% as of 11:00 a.m. EDT on Tuesday after the wireless spectrum specialist announced it had received a "superior proposal" to AT&T's previous acquisition bid.Straight Path stock jumped 150% two weeks ago when AT&T offered $95.63 per share, or a total transaction value of $1.6 billion.